1. Field of the Invention
The present invention relates to an apparatus and system for protecting vehicle occupants from injury. More specifically, the present invention relates to an inflatable curtain module implementing a dual flow inflator.
2. Description of Related Art
The inclusion of inflatable safety restraint devices, or airbags, is now a legal requirement for many new vehicles. Airbags are typically installed in the steering wheel and in the dashboard on the passenger side of a car. In the event of an accident, an accelerometer within the vehicle measures the abnormal deceleration and triggers the expulsion of rapidly expanding gases from an inflator. The expanding gases fill the airbags, which immediately inflate in front of the driver and passenger to protect them from impact against the windshield. Side impact airbags, known as inflatable curtains, have also been developed in response to the need for protection from impacts in a lateral direction, or against the side of the vehicle. An inflatable curtain may have one or more separately inflated cushions.
Side impact cushions are often designed to unfold or unroll downward to inflate beside a person to keep the person from hitting the door or window during lateral impact. Since a vehicle occupant may be leaning forward, reclined in the seat, or at any position between, such cushions are often made somewhat long to ensure that the occupant hits the cushion. If multiple cushions are fed by a single inflator positioned either fore or aft of the cushions, an especially long gas flow path exists between the inflator and the cushion furthest from the inflator. Thus, the outermost extents of the inflatable curtain may receive insufficient inflation gas pressure to inflate to the optimal protective pressure.
Even with somewhat shorter cushions, rapid and even inflation can be difficult to achieve with known inflator designs. Many existing inflators eject inflation gases outward radially; consequently, the inflation gases are not propelled along the length of the cushion, but are directed into the cushion near the inflator. The outer regions of the cushion are still inflated later than those closest to the inflator.
Additionally, some inflatable curtains are somewhat expensive due to the need for multiple inflators, attachment mechanisms, and the like. Many inflatable curtains require the use of a “gas guide,” or conduit that conveys gas from the inflator to the inflatable curtain. Some known inflators require the use of multiple initiators that add to the manufacturing expense and manufacturing time of the inflator.
Furthermore, many inflators produce thrust upon activation. As a result, somewhat complex attachment mechanisms must often be used to affix the inflators to the vehicle to ensure that the inflators do not dislodge themselves during deployment. Such additional parts increase the cost of the inflatable curtain as well as the time and expense required to install the inflatable curtain in a vehicle.
Another shortcoming of current inflatable curtain modules is the problem of requiring an inflator for each inflatable curtain. Often each inflatable curtain employed in an inflatable curtain module, requires its own inflator. This can become cost prohibitive because of the cost of inflators and the assembly costs.
A further problem with current inflatable curtain modules is the requirement for an inflatable curtain module to be designed specifically for an individual automobile. The inflatable curtain must be sized and manufactured for a specific vehicle design. Each new vehicle introduced or each vehicle employing an inflatable curtain requires a newly designed inflatable curtain. These constraints can cause undue costs and design time in employing an inflatable curtain in a vehicle.
Accordingly, a need exists for an inflatable curtain module capable of employing a dual flow, biaxial inflator. A need further exists for an inflatable curtain module having at least two differently sized inflatable cushions. A need also exists for an inflator capable of being interchangeable with inflatable curtains of different sizes. There is also a need for an inflatable curtain module capable of employing two inflators to provide a uniform gas input to a generally large cushion.
A need also exists for an inflator capable of being implemented within an inflatable curtain module for inflating two separate inflatable curtains. There is a further need for a configuration of inflators to inflate a substantially long inflatable curtain. A need is further present for a system employing multiple generic sizes of inflatable cushions and inflators to create a wider range of inflatable curtain modules.